Among the fundamental forces, which one of the following is the strongest force?

Which of the following pairs of nuclei represents isotones?

Who discovered the neutron?

Show that the volume of a nucleus is proportional to its atomic mass number $A$.

What is the particle $x$ in the following nuclear reaction :
${ }_4^9 Be+{ }_2^4 He \rightarrow{ }_6^{12} C+x$

In a periodic table,the average atomic mass of magnesium is given as $24.312 \; u$. This average value is based on their relative natural abundance on Earth. The three isotopes and their masses are $_{12}^{24} Mg \; (23.98504 \; u)$,$_{12}^{25} Mg \; (24.98584 \; u)$,and $_{12}^{26} Mg \; (25.98259 \; u)$. The natural abundance of $_{12}^{24} Mg$ is $78.99 \%$. Calculate the abundances of the other two isotopes.